The Mitochondrial Eve

[The Drunk Girl]

Today in my Microbiology class my professor asked the class whose DNA was found in the mitochondria.

A) The mother's
B) The father's
C) Both

The answer is A, the mother's. Dr. Pierce didn't go into detail about why our father's isn't found here, however she did make a side note that scientist had tracked everyone in the world's DNA back to one woman in Africa from roughly 200,000 years ago. For obvious reasons this peaked my interest and I made a note of what this woman had been named: "The Mitochondrial Eve."

Since, I have been home I googled (sorry Michael) this Eve to see what there is to know. It seems as if this was quite a big ordeal when this evidence came about in 1987 (no wonder why I don't remember, I was only 2! :lol:), but over the years new evidence proved that this could be wrong.

I merely found this topic amusing and thought I would share this neat little factoid with you all. Here's a pretty good article (http://www.trueorigin.org/mitochondrialeve01.asp) I found on it. :)

[Michael]

Yes, the "Mitochondrial Eve" theory was very controversial because it cuts the legs out from underneath all racist arguments.

It also impinges upon a related archeology argument about the origin of humans (out of Africa theory).

I remember the uproar at the time. I've never considered the matter controversial at all.

[Zarquon]

out of all hypothesis's regarding human origins, the out of Africa one is the one supported by the most number of scientists and also the most credible. The name, however, is rather irksome(evolution≠genesis).

[SMadsen]

Today in my Microbiology class my professor asked the class whose DNA was found in the mitochondria.

A) The mother's
B) The father's
C) Both

The answer is A, the mother's. Dr. Pierce didn't go into detail about why our father's isn't found here, however she did make a side note that scientist had tracked everyone in the world's DNA back to one woman in Africa from roughly 200,000 years ago. For obvious reasons this peaked my interest and I made a note of what this woman had been named: "The Mitochondrial Eve."

Since, I have been home I googled (sorry Michael) this Eve to see what there is to know. It seems as if this was quite a big ordeal when this evidence came about in 1987 (no wonder why I don't remember, I was only 2! :lol:), but over the years new evidence proved that this could be wrong.

I merely found this topic amusing and thought I would share this neat little factoid with you all. Here's a pretty good article (http://www.trueorigin.org/mitochondrialeve01.asp) I found on it. :)
You do know that the "good article" you link to is from a creationist book by Apologetics Press, right?

It contains the usual distortions that are thrown in the face of little kids to keep from from wandering off of a path they're supposed to follow blindly.

For example, they use a study by Parson and Howell and not only take it out of context but omit to add that it concerns a single method that studies a limited section of mtDNA and therefore isn't representative of mutation rates in the main section of mtDNA. That particular example continues to circle the creationist sites and is therefore singled out (http://www.talkorigins.org/indexcc/CB/CB621_1.html) in talkorigins.org's archive (it's also addressed in a far more extensive way by Alec MacAndrew here (http://www.evolutionpages.com/Mitochondrial%20Eve.htm), where, for example, the truncated and misrepresented quotes used in the article are returned to a more proper context).

[Michael]

out of all hypothesis's regarding human origins, the out of Africa one is the one supported by the most number of scientists and also the most credible. The name, however, is rather irksome(evolution≠genesis).
I have no objections to the 'out of Africa' theory, or the 'mitochondrial eve' theory. I was just stating that I remember these and rival theories taught in my university 'intro to anthro' course. ;)

Btw, if you are into the topic of human evolutionary development, I tend to favor the 'neotony' school of interpretation. I find the general topic endlessly fascenating (evolution necessarily implies that every aspect of human development has a reason for it - ergo, speculating about the reasons is fun/interesting).

[phungus420]

Btw, if you are into the topic of human evolutionary development, I tend to favor the 'neotony' school of interpretation. I find the general topic endlessly fascenating (evolution necessarily implies that every aspect of human development has a reason for it - ergo, speculating about the reasons is fun/interesting).

YOu should look into some of the more recent (after 2000) theories and evidence supporting said theories, on sexual selection in humans. Really interesting stuff there. Humans appear to have an ingraned atraction toward intelligence that is quite strong and is at least on par with a female's atraction toward high testosterone phisiological queues while ovulating.

[Lily]

YOu should look into some of the more recent (after 2000) theories and evidence supporting said theories, on sexual selection in humans. Really interesting stuff there. Humans appear to have an ingraned atraction toward intelligence that is quite strong and is at least on par with a female's atraction toward high testosterone phisiological queues while ovulating.


The women up here must have been absent from school that day. That's all I'm sayin'.

[dilettante]

If all humans can be traced to a single female, that would imply that the first human societies were matrilineal, with children being raised as part of the mother's clan rather than the fathers.
Son who had children with women outside the family must have given them up to the mother's family (otherwise they would introduce some other mother's mitochondrial DNA into the line); daughters who had children with men from outside the family must have kept the children so the family could grow. Thus, each family/kinship group could have an unbroken succession of mothers->daughters, and eventually one such group beat out all the others.

[SMadsen]

If all humans can be traced to a single female, that would imply that the first human societies were matrilineal, with children being raised as part of the mother's clan rather than the fathers.
Son who had children with women outside the family must have given them up to the mother's family (otherwise they would introduce some other mother's mitochondrial DNA into the line); daughters who had children with men from outside the family must have kept the children so the family could grow. Thus, each family/kinship group could have an unbroken succession of mothers->daughters, and eventually one such group beat out all the others.
A so-called Most Recent Common Ancestor is all that can be concluded. It says nothing about societal norms or anything.

The only key point for the MRCA is that, at some time, a sexually isolated population has arisen and from that population all other populations have arisen. How genes recombined is irrelevant. We can only find out when.

Basically, the sperm cell contains 100 to 1000 times less mitochondria than the egg cell. Add to that that the sperm cell is merely a vehicle for DNA. The rest of the cell is of no use. Some of it breaks off on entry and most of the remaining cell is simply devoured by the egg (Y. Nishimura et al showed in 2006 via staining how sperm mitochondrias were actually eaten up by the egg cytoplasma). So, essentially no paternal mtDNA is left in the egg. If some should be left, it hasn't been shown to recombine other than in a few, abnormal cases. Therefore, it's pretty safe to say that mtDNA is maternally inherited. And that's really all there is to the usefulness of mtDNA; it shows lineage on the basis of mutation rates only. There is no recombination to consider.

[The Drunk Girl]

You do know that the "good article" you link to is from a creationist book by Apologetics Press, right?

It contains the usual distortions that are thrown in the face of little kids to keep from from wandering off of a path they're supposed to follow blindly.

For example, they use a study by Parson and Howell and not only take it out of context but omit to add that it concerns a single method that studies a limited section of mtDNA and therefore isn't representative of mutation rates in the main section of mtDNA. That particular example continues to circle the creationist sites and is therefore singled out (http://www.talkorigins.org/indexcc/CB/CB621_1.html) in talkorigins.org's archive (it's also addressed in a far more extensive way by Alec MacAndrew here (http://www.evolutionpages.com/Mitochondrial%20Eve.htm), where, for example, the truncated and misrepresented quotes used in the article are returned to a more proper context).

Well, I will give you that. I will admit that I went into this blindly and should have paid more attention to "good article" I presented. At the time, it had what I thought were decent points on both sides. As I said, I found the topic interesting and somewhat exciting to learn more about. But you live and learn, right? :)

I do want to add, that I figured there was more to this than just tracing everyone back to one particular female. As other articles I have read suggest (and to me does seem logical), factors such as mutations and women not having a daughter can cause a flaw in the lineage that has been traced back. I really have no feelings either way on how true or not this is.

[SMadsen]

The Drunk Girl, I just want to say that it wasn't my purpose to accuse you of proselytizing or anything, only to make a warning about the article :)

[The Drunk Girl]

The Drunk Girl, I just want to say that it wasn't my purpose to accuse you of proselytizing or anything, only to make a warning about the article :)

I know. That is why I said "you live and learn." I got a tad overly excited to share and didn't pay attention to the source. No worries here at all and I understand that you were trying to help. I'm actually glad that you pointed that out.

[dannydesiliva]

I hope the title explains my question.

I understand that Y-Chromosomal Adam is the most-recent y-chromosomal common ancestor of every living human. I *think* I understand that there may be other recent common male ancestors, but they wouldn't have passed on their Y-chromosomes to every living human without an unbroken patrilineal chain (as required to pass a common y-chromosome?). I get that it has been shown that every human alive today has inherited mitochondrial DNA from Mitochondrial Eve. And I *sorta* get that means that Mitochondrial Eve must be the most-recent female common ancestor for the human population.

So, how come we don't all have common mitochondrial DNA from Y-Chromosomal Adam's mother?

[SMadsen]

I hope the title explains my question.

I understand that Y-Chromosomal Adam is the most-recent y-chromosomal common ancestor of every living human. I *think* I understand that there may be other recent common male ancestors, but they wouldn't have passed on their Y-chromosomes to every living human without an unbroken patrilineal chain (as required to pass a common y-chromosome?). I get that it has been shown that every human alive today has inherited mitochondrial DNA from Mitochondrial Eve. And I *sorta* get that means that Mitochondrial Eve must be the most-recent female common ancestor for the human population.

So, how come we don't all have common mitochondrial DNA from Y-Chromosomal Adam's mother?
If you get that "every human alive today has inherited mitochondrial DNA from Mitochondrial Eve" then why would you think that the Y-Chromosal Adam and his mom did not inherit mitochondrial DNA from Mitochondrial Eve?

[JHC]

Mitochondria are fascinating. They are organelles (little organs) within a cell but no other organelle has it's own DNA completely separate from the DNA found in the nucleus of the cell in which they exist.

Other organelles include ribosomes - they take orders brought over from the cells DNA and create proteins out of them. More precisely, the DNA strand is read by RNA in little sections called codons. Codons are sets of three nucleotides - the old guanine, cytosine, adenine and thymine we all learned in BIO 101. Each set of three nucleic acids provides a single amino acid. Ribosomes string these amino acids together as the building blocks of proteins.

Mitochondria is the cells power house. They create energy from chemicals. Imagine if mitochondria were free living prokaryotic organisms like bacteria? it isn't hard to do. In fact, the widely accepted theory is that mitochondria were once free living organisms ingested by other free living organisms in a symbiotic relationship and that is why eukaryotic cells have mitochondria today. Mitochondria never gave up their own DNA. They need it to make proteins and enzymes for their own functions of churning out ATP.

In theory then, the true Mitochondrial Eve may actually be a 350 billion year old single celled organism with maybe a flagella instead of feet and fimbria instead of hands. :D She wouldn't be a she or a he but we would call it Eve because the mtDNA was passed matrilineally.

[JHC]

Today in my Microbiology class my professor asked the class whose DNA was found in the mitochondria.

A) The mother's
B) The father's
C) Both

The answer is A, the mother's. Dr. Pierce didn't go into detail about why our father's isn't found here, however she did make a side note that scientist had tracked everyone in the world's DNA back to one woman in Africa from roughly 200,000 years ago. For obvious reasons this peaked my interest and I made a note of what this woman had been named: "The Mitochondrial Eve."

Since, I have been home I googled (sorry Michael) this Eve to see what there is to know. It seems as if this was quite a big ordeal when this evidence came about in 1987 (no wonder why I don't remember, I was only 2! :lol:), but over the years new evidence proved that this could be wrong.

I merely found this topic amusing and thought I would share this neat little factoid with you all. Here's a pretty good article (http://www.trueorigin.org/mitochondrialeve01.asp) I found on it. :)
Tackling the article:
In an effort to degrade the matrilineal descent of mtDNA, the article sites the case of the 28 year old man with mitochondrial myopathy whose muscle cells contained 90% of the patrilineal mtDNA instead of matrilineal mtDNA. The author reiterates the 90% figure and adds an exclamation point for emphasis because 90% is a big number.
But what is he really saying?
The 28 year old man had a frame shift caused by deletion of a nucleic acid. The entire chain of DNA from that point on, would begin coding for nonsense proteins or no proteins at all.
Mitochondrial myopathy can lead to muscle weakness and loss (including heart and lungs), dimentia, mental retardation, blindness, deafness, and a whole slew of other issues. The bigger the mutation, the less chance of survival. That's called natural selection. Not a good example.
In fact, in every example they site, the recombination is said to be rare.
It's as if a thin crack in a theory is all the reason they need to disregard all evidence in support of that theory.